Gilead's combo shows no resistance in HIV

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Dive Brief:

Results from the Phase 3 trials 1489 and 1490 of the combination regimen of bictegravir with the dual-NRTI backbone Descovy (emtricitabine/tenofovir alafenamide) in treatment-naïve HIV-positive adults showed that the combo was non-inferior to regimens containing GlaxoSmithKline's Tivicay (dolutegravir) and a dual-NRTI backbone. The data strongly supports results released earlier in the year.

In the 1489 study, Gilead's combo and ViiV Healthcare's Triumeq (abacavir/dolutegravir/lamivudine) both dropped HIV-1 RNA levels to less than 50 copies/mL, the primary endpoint, in over 90% of patients, with a difference of 1.6% (p=0.78). In the 1490 study, which compared bictegravir plus Descovy with Tivicay plus Descovy, the Gilead combo hit the primary endpoint in 89.4% of patients, compared with 92.9% of the patients for Tivicay plus Descovy (p=0.12).

There was no treatment-emergent resistance in either of the 48-week studies. These data, and data from the ongoing 48-week studies of the Gilead combo (1844 and 1878), formed part of the EU and U.S. regulatory submissions.

Dive Insight:

Gilead has been fighting falling sales for its hepatitis C drugs arsenal, partly as a result of its own success – the drugs have been highly curative in HCV patients and have eroded the backlog of patients who were waiting for treatment. The sales of Sovaldi (sofosbuvir) and Harvoni (ledipasvir/sofosbuvir) are expected to be around $7.5 to $9 billion this year, down from $14.8 billion in 2016. Gilead has been adding new combinations, such as Vosevi (sofosbuvir/velpatasvir/voxilepravir), approved this month, but it can't rely on its Sovaldi franchise forever, as more patients are cured.

Because of this, the company is looking to its HIV franchise, and this latest data, presented at the 9th IAS Conference on HIV Science (IAS 2017) in Paris, builds on the Phase 3 findings announced in May. The combination of an integrase inhibitor plus a dual-NRTI backbone have become a standard of care for initial treatment of HIV, according to Joel Gallant, medical director of Specialty Services at Southwest CARE Center in Santa Fe, N.M. and lead author of Study 1489. The combination of bictegravir and Descovy offers another choice, including for those patients with renal impairment.

"In clinical trials, the investigational regimen of BIC/FTC/TAF has been well tolerated with low rates of discontinuations due to adverse events, a high barrier to resistance and few drug interactions,” Gallant added.

In a note to clients, analysts at Jefferies suggested that the lower responses for Gilead in the 1490 study were as a result of no-show patients rather than challenges with the drug. Jefferies analysts also suggested that the Gilead combination may have better resistance data than GlaxoSmithKline combinations.

Gilead's falling HCV product sales, reported back in May in the first quarter, led to questions about potential mergers and partnerships in the conference call. Despite some hints, nothing has come of these as yet, but it may depend on the future of the company's strengthening HIV franchise.